Stefan Ellinger

Palladium-Catalyzed Trifluoromethylation of (Hetero)Arenes with CF3 Br.

The CF3 group is an omnipresent motif found in many pharmaceuticals, agrochemicals, catalysts, materials, and industrial chemicals. Despite well-established trifluoromethylation methodologies, the straightforward and selective introduction of such groups into (hetero)arenes using available and less expensive sources is still a major challenge. In this regard, the selective synthesis of various trifluoromethyl-substituted (hetero)arenes by palladium-catalyzed C-H functionalization is herein reported. This novel methodology proceeds under comparably mild reaction conditions with good regio- and chemoselectivity. As examples, trifluoromethylations of biologically important molecules, such as melatonin, theophylline, caffeine, and pentoxifylline, are showcased.

Tetracyanido(difluorido)phosphates M+[PF2(CN)4]−†

The systematic study of the reaction of M[PF6 ] salts and Me3 SiCN led to a synthetic method for the synthesis and isolation of a series of salts containing the unprecedented [PF2 (CN)4 ](-) ion in good yields. The reaction temperature, pressure, and stoichiometry were optimized. The crystal structures of M[PF2 (CN)4 ] (M=[nBu4 N](+) , Ag(+) , K(+) , Li(+) , H5 O2 (+) ) were determined. X-ray crystallography showed the exclusive formation of the cis isomer in accord with (31) P and (19) F solution NMR spectroscopy data. Starting with the K[PF2 (CN)4 ] the room temperature ionic liquid EMIm[PF2 (CN)4 ] was prepared exhibiting a rather low viscosity.

Lewis Acid Catalyzed Synthesis of Cyanidophosphates.

Salts containing new cyanido(fluorido)phosphate anions of the general formula [PF6-n(CN)n](-) (n=1-4) were synthesized by a very mild Lewis-acid-catalyzed synthetic protocol and fully characterized. All [PF6-n(CN)n](-) (n=1-4) salts could be isolated on a preparative scale. It was also possible to detect the [PF(CN)5](-) but not the [P(CN)6](-) anion. The best results with respect to purity, yield, and low cost were obtained when the F(-)/CN(-) substitution reactions were carried out in ionic liquids.